Infusion of drugs

ABSTRACT

An at least partly implantable system for injecting a substance into a patient&#39;s body. The system comprises at least one flexibly bendable infusion needle with a tip end of each of said at least one infusion needle arranged in at least one first housing for penetrating the first housing&#39;s outer wall in at least one penetration area and having the respective other end arranged in at least one second housing, the first and second housings being adapted for implantation inside the patient&#39;s body, wherein the at least one second housing is provided for implantation inside the patient&#39;s body remote from the at least one first housing and wherein the injection needle is sufficiently long to bridge the distance from the at least one second housing for remote implantation to the at least one first housing and further through the first housing up to the outer wall of the first housing. The system further comprises at least one drive unit adapted for being coupled to the at least one infusion needle and arranged at least for advancing the tip end of the at least one infusion needle so that the at least one infusion needle penetrates with the tip end or ends thereof said at least one first housing&#39;s outer wall in said at least one penetration area.

This application is a continuation of U.S. application Ser. No.15/924,362, filed 19 Mar. 2018, and issued as U.S. Pat. No. 10,383,994,which is a continuation of U.S. application Ser. No. 14/611,296, filedFeb. 2, 2015, and issued as U.S. Pat. No. 9,919,098, which is acontinuation of U.S. application Ser. No. 13/123,059, filed Apr. 7,2011, and issued as U.S. Pat. No. 8,945,054 on Feb. 3, 2015, which isthe U.S. national phase of International Application No. PCT/EP09/07284,filed Oct. 9, 2009, which designated the U.S. and claims the benefit ofU.S. Provisional Application No. 61/136,885, filed on Oct. 10, 2008, theentire contents of each of which are hereby incorporated by reference inthis application.

BACKGROUND OF THE INVENTION

The present invention relates generally to the infusion of a substance,in particular drugs, into a patient's body, and, more specifically, tothe stimulation of penis erection.

When a male is stimulated erotically, connections between arteries andveins are closed (arteriovenous anastomoses) so that blood which isnormally able to bypass the empty spaces or sinuses of the corporacavernosa is retained in the penis.

The main vessels supplying the blood to the cavernous spaces in theerectile tissue of the corpora cavernosa are the deep arteries of thepenis. They are therefore heavily involved in the erection of the penis.They give off numerous branches—the helicine arteries—that open directlyinto the cavernous spaces.

When the penis is flaccid, these arteries are coiled, restricting bloodflow. However, the smooth muscle in the coiled helicine arteries relaxesas a result of parasympathetic stimulation. In their relaxed state, thehelicine arteries straighten, enlarging their lumina and allowing bloodto flow into and dilate the cavernous spaces in the corpora of the penisat arterial pressure. In combination with the bulbospongiosus andischiocavernosus muscles compressing the veins egressing from thecorpora cavernosa, the erectile bodies of the penis become enlarged andrigid, and an erection occurs.

Patients suffering from erectile dysfunction can cause the penis tobecome turgid by injecting into the corpora cavernosa a medicament, suchas papaverine or prostaglandin E1, causing the smooth muscles to relax.The patients have to learn a certain technique under doctor'ssupervision in order to be able to properly inject the medicament ineach of the corpora cavernosa. Only after about 15 minutes afteradministration of the medicament will the medicament become effective.The entire procedure is inconvenient, the more so as the medicament mustusually first be mixed together from a dry substance and a salinesolution. Only as a dry substance (and typically cooled) are theavailable medicaments stable.

Furthermore, proper administration and dosing is critical since themedicament may be transported with the blood into other regions of thepatient's body if the injection is not done properly.

Recently, a different method has become known under the brand Muse®. Inthis method, a plastic rod comprising the medicament alprostadil isinserted into the urethra. Upon pressing a button, the alprostadil isreleased from the rod into the urethra. After removal of the plasticrod, the penis is rolled between the palms of the hands so that themedicament dissolves, distributes and is absorbed through the urethrawall. However, proper dosage and administration is also critical in thismethod.

The afore-mentioned problems are not limited to the administration ofdrugs stimulating penis erection. Similar problems can also occur inother applications where a substance is to be injected frequently.

It is therefore the object of the present invention to improve theadministration of a drug into a patient's body, and more specifically toimprove the stimulation of a penis erection so that the entire processis more reliable and more convenient for the patient.

SUMMARY OF THE INVENTION

The essence of the invention lies in injecting a substance into thepatient's body using at least one implantable infusion needle. This willgreatly improve the patient's comfort as he no longer needs to piercehimself with the infusion needle, which for many people is not an easytask. Furthermore, due to the permanent implantation of the infusionneedle, the injection will always occur at the proper location, saidlocation being selected such that the drug is most effective. Whilethere are many conceivable technical variations for injecting the drugthrough the infusion needle into the patient's body, such injections aredefinitely more convenient for the patient once the infusion needle hasbeen implanted as compared to the alternative of injecting the drugmanually from outside the patient's body.

According to the invention, the at least one implantable infusion needleis long and flexibly bendable, with the respective tip end or ends beingdisposed within (at least one) first housing so as to penetrate thefirst housing's outer wall or walls in at least one penetration area,preferably in two or more different penetration areas. As will bedescribed below, two or more infusion needles may be provided in orderto inject the drug in the two or more different penetration areas, or asingle infusion needle may be provided along with an appropriate driveunit for displacing the tip end of the infusion needle so as topenetrate the first housing's outer wall in the respective differentpenetration areas. Arranging the infusion needle's tip end in said firsthousing prevents any fibrosis from growing into the infusion needle.

The use of one or more long flexible needles is chosen for reasons ofspace constraints in the area where the injection of the drugs has tooccur. The at least one first housing accommodating the tip end of suchlong infusion needle or needles can be kept small and, therefore, can bearranged conveniently in close proximity to a constrained injectionarea, where the tip end can penetrate the outer wall of the firsthousing upon advancement of the long infusion needle. The respectiveother end of the long, flexibly bendable infusion needle or needles,i.e. the infusion needle's rear end, is arranged in a second housingwhich can be implanted inside the patient's body remote from the firsthousing in an area with fewer space constraints. The injection needle issufficiently long to bridge the distance from the second housing forremote implantation to the first housing and further through the firsthousing up to the outer wall of the first housing to be penetrated bythe needle. Thus, since the respective other end of the infusion needleor needles is remotely implanted within the patient's body, othercomponents of the system cooperating with the rear end of the infusionneedle may also be implanted remote from the injection area, such as areservoir for storing the substance to be injected, a pump for advancingthe substance from the reservoir to the infusion needle and furtherthrough the needle into the patient's body, a motor for actuating thesystem's active parts, at least one drive unit for—at least—advancing(and possibly retracting) the infusion needle or needles in such a waythat it penetrates at least one penetration area—preferably two or moredifferent penetration areas—so as to allow for injecting the substancethrough said penetration area or areas via the at least one infusionneedle, and so forth. In a particularly preferred embodiment, the tipend of the infusion needle is advanced by advancing the entire needlefrom the infusion needle's rear end. It is particularly advantageous toarrange at least a part of the drive unit, preferably the entire driveunit, for advancing the infusion needle within the second housing. Morepreferably, a reservoir and/or most or all of the active parts, such asa motor, a pump and the like, may also be implanted remotely within thepatient's body and, more preferably, may be accommodated in the remotelyimplanted second housing, whereas the first housing only includespassive elements, possibly including passive elements of the drive unit.In this context it is to be understood that a drive unit according tothe present invention includes not only the drive itself, such as anelectric motor, but also those components which are involved intransforming the driving energy provided by the drive into movement ofthe at least one needle, such as transmission gears and the like. Othercomponents such as an energy source, a control unit and/or a dataprocessing device may be extracorporal to complete the system. However,it is preferred that the aforementioned components be implanted as well,preferably forming an integral part with the remaining components of thesystem so as to be implantable as a unitary piece with the secondhousing.

The infusion needle or needles may rest at the implantation site over along time either for single use or for multiple use. For instance, whereit is likely that a patient will suffer an allergic attack, such assevere allergic reactions affecting e.g. the respiratory tract, in thenear future or possibly only within a year or two, the infusion needleand possibly the entire system may be implanted in the patient's bodyfor single use at the appropriate time. Over time, fibrosis will grow onthe system. However, at the time of use, the infusion needle may beadvanced by the drive unit so as to penetrate any fibrosis, therebyallowing immediate drug delivery from the reservoir through the tip endof the infusion needle into the patient's body. Where the infusionneedle is implanted adjacent a blood vessel, the tip end of the infusionneedle may be advanced into the blood vessel without any risk offormation of thrombosis (nicht fibrosis?) prior to use.

Where the system is implanted for multiple use, the drive unit ispreferably configured for advancing and retracting the tip end of theinfusion needle. Thus, each time when the drug is delivered to thepatient, the infusion needle will be advanced, the drug injected and theinfusion needle retracted again.

More specifically, in the case of multiple use, it is even preferredwhen the at least one drive unit is coupled to the at least one infusionneedle so as to advance and retract the tip end of the at least oneinfusion needle in such a way that it penetrates at least two differentpenetration areas within the housing's outer wall, so as to allow forinjecting the substance through said at least two different penetrationareas via the at least one infusion needle. The distance between the twodifferent penetration areas to be penetrated by the at least oneinfusion needle is selected such that the respective parts of thepatient's body are pierced whenever the drug is to be injected.

This structure can advantageously be used for stimulating peniserection, in which case the first housing or housings are adapted forimplantation inside the patient's body adjacent to both the right andleft corpus cavernosum of the patient's penis and/or the two deeparteries of the right and left corpus cavernosum and/or adjacent tomuscle tissue regulating blood flow through the patient's left and rightcorpus cavernosum and/or in sufficiently close proximity to another typeof tissue allowing both the first and second corpus cavernosum to becometurgid when the particular drug is injected thereinto. The at least oneinfusion needle then penetrates the at least two different penetrationareas either simultaneously (e.g. where a plurality of needles, i.e. atleast two needles, are provided) or in immediate time succession (e.g.where a single needle is provided). Preferably, a single command orsingle action from the patient is sufficient for injecting the substancethrough the at least two penetration areas, either due to acorresponding mechanical structure of the drive unit or due to asuitably configured control unit controlling the drive unit. This willmake the handling of the system easy for the patient.

Where two different penetration areas are pierced in immediate timesuccession, the time delay between the penetration of the first and thesecond of the penetration areas is preferably as short as possible, morepreferably less than 120 seconds, and most preferably less than 60seconds. This can be achieved by means of a properly controlled driveunit. A longer time delay would be inconvenient for the patient.Therefore, it is preferred that, once the infusion needle has beenretracted from a first of the two penetration areas, it is immediatelyadvanced to the second of the penetration areas.

While it is possible according to one aspect of the invention toactively open the outer wall or walls of the at least one first housingfor allowing the infusion needle to penetrate the outer wall, it ispreferred according to another aspect of the invention to arrange theneedle so as to penetrate the outer wall by piercing through the outerwall. For that purpose, the outer wall may either comprise flaps to bepushed aside by the infusion needle as the infusion needle is advanced,or the outer wall may be made at least in the penetration areas from amaterial which is self-sealing in respect of penetrations resulting fromthe at least one infusion needle. This is generally known from WO2007/051563 disclosing an implantable infusion device with a singleinfusion needle entirely contained in a housing to be implanted adjacentan injection area, the needle being laterally displaceable within thehousing and both advanceable and retractable through the housing's outerwall. While the entire first housing may be made from the self-sealingmaterial, it is advantageous for stability reasons if the self-sealingmaterial forms at least one window area in the outer wall, the windowarea being positioned for penetration by the tip end of the at least oneinfusion needle. The window area may be formed by a self-sealingpenetration membrane which is preferably integrated in the outer wall bypress fitting it into the outer wall. Typically, the self-sealingmaterial would be made from a polymer material which preferablycomprises silicone. Other biocompatible polymer materials, such aspolyurethane and the like, may be employed as well. The self-sealingmaterial may also be a composite material. A particularly preferredembodiment of such composite material comprises at least one outershape-giving layer and a self-sealing soft material contained within theouter layer. Thus, the outer layer forms a shell for the soft material.The outer layer may be made from a biocompatible polymer, such as one ofthose polymers mentioned above, and preferably the self-sealing softmaterial may be a gel.

Instead of a self-sealing material, the part of the outer wall of thefirst housing to be penetrated by the infusion needle may comprise oneor more flaps in the penetration areas through which the infusion needleor needles can pass. This can reduce the force needed for the infusionneedle to penetrate the outer wall, as compared to the penetration of aself-sealing membrane. The flap is preferably arranged to be pushedaside by the infusion needle upon advancement of the infusion needle.

Alternatively, the outer wall may comprise at least one door in thepenetration areas. A drive is connected to the door for actively openingthe door so as to allow for the infusion needle to be advanced throughthe opened door. Again, the door may comprise a flap, such as aresilient, normally closed flap. It is particularly preferred if thedrive connected to the door forms part of the drive unit coupled to theinfusion needle. More specifically, the arrangement may be such thatadvancement of the infusion needle by means of the drive unitsimultaneously causes the drive to open the door.

The at least one infusion needle preferably has a tube-like body closedat the tip end and provided with a laterally arranged delivery exit portfor delivery of the drug into the particular body part. Therefore, theneedle will not cut out any material but will simply divide it duringpenetration. Thus, when the needle penetrates any material, such asfibrosis and/or the self-sealing penetration membrane, there will be nomaterial entering and blocking the drug delivery passageway.

As mentioned above, a separate infusion needle may be provided for eachof the two or more penetration areas. Thus, where injection is desiredto occur in two or more different areas, such as for provoking peniserection, two or more separate infusion needles may be advanced throughthe corresponding penetration area of the respective first housing orhousings—preferably simultaneously—and retracted again after injection.

According to a preferred embodiment of the invention, a plurality of twoor more infusion needles is provided for each of the differentpenetration areas and arranged for penetrating different penetrationsites within each of said different penetration areas. This allows forpenetrating different sites within each penetration area at differenttimes, thereby giving the human tissue time to recover from the piercingby the infusion needle. This can be achieved with a drive unit suitablyconfigured to advance and retract one infusion needle in each of saiddifferent penetration areas at one time, and to advance and retract adifferent infusion needle in each of said different penetration areas ata different time.

The drive unit may be such that the infusion needle is advanced and/orretracted by turning the infusion needle or by turning an elementcooperating with the infusion needle. More specifically, the drive unitfor advancing and retracting the infusion needle may comprise a screwdrive connection. For instance, the drive of the drive unit may turn ascrew threadingly engaged with a rack coupled to the infusion needle sothat rotation of the screw will cause the infusion needle to be advancedor retracted. The screw and rack of the screw drive connection arepreferably accommodated in the remotely implanted second housing but mayalso be arranged in the housing accommodating the tip end of the needle.Instead of the screw, the infusion needle itself may be rotated by meansof a suitable drive so that threading on the needle engaging a fixedlymounted rack causes the infusion needle to advance or retract uponrotation of the infusion needle. Between the first and second housings,the infusion needle is preferably guided in a sheath, so as to reducefriction and prevent growth of fibrosis that might hinder movement ofthe needle.

The tip ends of a plurality of infusion needles may be contained in acommon housing in spaced apart relationship, with the drive unit beingconfigured to advance and retract the tip ends of the infusion needlesso as to penetrate the outer wall of the common housing in said at leasttwo different penetration areas, again preferably simultaneously.Placing the tip ends in a common housing simplifies the procedure forfixing the needles in place close to the injection areas. Furthermore, asingle drive unit may be used for advancing and retracting the tip endsof the plurality of infusion needles, this making the entire system lessvoluminous.

According to a particularly preferred aspect of the invention, the tipend or ends of the at least one infusion needle are laterally movable,so as to vary the penetration sites within the particular penetrationareas of the first housing's outer wall, thereby varying the injectionsite within the particular injection area in the patient's body. As setout above, frequent piercing of the same body part may cause irritation,eventually making further piercing difficult or even impossible.Variation of the injection site by laterally displacing the needle uponeach injection cycle may overcome such problems. Accordingly, the atleast one drive unit is preferably configured to laterally displace thetip end or ends of the at least one infusion needle to differentpenetration sites within each of said different penetration areas.

More specifically, the drive unit is preferably configured to laterallydisplace the tip ends of two or more infusion needles simultaneously.This can be achieved e.g. by jointly mounting the tip ends of theinfusion needles on a movable carriage of the drive unit, such as aturntable and/or a shuttle, possibly in the form of a slide. Thus, thedrive unit for advancing and retracting the tip ends of the infusionneedles is preferably configured so as to also laterally displace thetip ends of the infusion needles each time the tip ends are advanced orretracted.

Thus, the lateral displacement and the advancement/retraction of the tipend or ends of the at least one infusion needle are coordinated. Thelateral displacement of the tip end may take place before and/or afteran injection. The mechanism may be such that after a certain number oflateral displacements or after lateral displacement over a predefineddistance, the tip end of the infusion needle is laterally returned toits initial position so that the next number of infusions will takeplace again at locations that have previously been penetrated by theneedle. It is even preferred to configure the drive unit such that thetip end or ends of the at least one infusion needle are displaced in atleast two different lateral directions. For instance, when the infusionneedle has laterally returned to its initial position, the next numberof infusions may take place somewhat laterally offset above or below thefirst number of penetration sites. This permits a two-dimensional arrayof penetration sites to be obtained.

The tip ends of two or more infusion needles may be arranged one abovethe other within a common first housing. Generally speaking, it ispreferable in such a situation that the direction of lateraldisplacement of the tip ends of the infusion needles within thedifferent penetration areas is different from, in particularperpendicular to, the direction of distance between the differentpenetration areas. Alternatively, where the infusion needles arearranged with great lateral distance between each other, the directionof lateral displacement of the tip ends of the infusion needles withineach of the two different penetration areas may generally be the same asthe direction of distance between the different penetration areas.

It is likewise possible to provide the tip end of a single infusionneedle within the first housing and to implant the first housing withinthe patient's body adjacent the two or more injection areas. In thiscase, the drive unit may be configured so as to laterally displace thetip end of the one infusion needle between various lateral positionssuch that the infusion needle can penetrate the first housing's outerwall in the different penetration areas. The distance of lateraldisplacement of the single infusion needle between the differentpenetration areas would amount to 3 mm, 4 mm, 5 mm or even more uponeach successive injection. Such successive injections are preferably inimmediate time succession, preferably not exceeding 120 seconds betweentwo injections, more preferably not exceeding 60 seconds. Mostpreferably, the drive unit will be adapted to initiate advancement ofthe one infusion needle to a second one of the plurality of penetrationareas once it has been retracted from a first one of the penetrationareas.

An implantable infusion device comprising a single, laterallydisplaceable infusion needle contained within a housing so as topenetrate the housing's outer wall at different penetration sites isgenerally known from previously mentioned WO 2007/051563. However, thisprior art device is neither intended nor configured for injecting drugssimultaneously or quasi-simultaneously in immediate time succession intwo or more different injection areas. The drive unit of the prior artdevice is instead configured to administer the drug at a differentpenetration site of a single injection area at each time of operation.For instance, the prior art device may be placed along a blood vessel soas to inject drugs at different injection sites within a singleinjection area of the blood vessel. Thus, the distance of lateraldisplacement of the tip end of the infusion needle between one injectionand a next following injection is not configured in the prior art devicesuch that different injection areas within the patient's body could bereached. Also, the prior art infusion device is not aimed at being usedfor the stimulation of penis erection. In addition, in the prior artinfusion device the entire infusion needle is accommodated in thehousing which is to be implanted next to the constrained injection area,thereby requiring that the drive unit for advancing and retracting thetip end of the infusion needle is also implanted in the same constrainedarea.

Turning back to the present invention, it is again preferable, when thepatient desires to perform another injection at a later point of time,that the single infusion needle does not penetrate the same penetrationsite within the particular penetration area of the housing's outer wall,but that the drive unit is configured to laterally displace the tip endof the one infusion needle to different penetration sites within each ofthe different penetration areas. Again, the direction of lateraldisplacement of the tip end of the one infusion needle within each ofthe different penetration areas may either be the same as the directionof lateral displacement of the tip end of the infusion needle betweenthe different penetration areas, or may be different from, in particularperpendicular to, the direction of lateral displacement of the tip endof the infusion needle between the different penetration areas.Depending upon the particular configuration of the system, this may beachieved with a single, multifunctional drive unit or with a pluralityof different drive units suitably arranged to work in coordinatedfashion. Even a combination of these alternatives is possible. Forinstance, when after a number of infusion cycles an infusion needle haslaterally returned to its initial position, the next number of infusionswithin the same penetration area may take place somewhat laterallyoffset above or below the first number of penetration sites. Thus, atwo-dimensional array of penetration sites can be obtained in eachpenetration area, thereby keeping the maximum dimensions of thepenetration areas at a minimum.

Where the first housing or at least the window area thereof is formedspherically, even a three-dimensional array of penetration sites throughthe first housing's outer wall can be obtained by means of a suitablyadapted drive unit for the needle displacement. This greatly increasesthe system's flexibility of use.

Regardless of the number of needles involved and regardless of theparticular penetration site array to be achieved, it is preferable toconfigure the drive unit such that the lateral displacement of the tipend of the infusion needle or needles is achieved automatically duringadvancement and/or retraction of the tip end of the needle or needles.For instance, where the infusion needle is mounted on a movable carriagefor the lateral displacement of the tip end of the needle, such as on aturntable or a shuttle, e.g. in the form of a slide, the drive unit maycomprise a stepper which is adapted to automatically advance the movablecarriage a predefined distance upon each advancement and/or retractionof the infusion needle.

Now, turning to the reservoir, it should be considered that long termstorage is not possible with many currently available drugs, this beingparticularly true of drugs stimulating penis erection. Where long termstorage is desired, the drug to be injected would typically be providedas a first substance and mixed with a second substance for injectionshortly before the injection is performed. Therefore, according to apreferred embodiment of the present invention, the reservoir of thesystem comprises at least one first compartment, e.g. for accommodatingan infusion liquid such as a saline solution, and at least one secondcompartment, e.g. containing a drug, in particular a drug in dry form,for mixing with the infusion liquid of the first compartment. The drugmay be in powder form and, more specifically, may be a freeze-drieddrug. In particular, the drug contained in the second compartment wouldbe a drug for stimulating penis erection. A mixing chamber may beprovided for mixing the substance from the first compartment with thesubstance from one or more of the at least one second compartment.

The number of the second compartments may be huge, such as 50 or more,in particular 100 or more. This would not constitute a particularproblem in terms of space constraints since the amount of drugs requiredfor each stimulation of penis erection is extremely little and wouldamount to a few micrograms. Furthermore, the reservoir may be adaptedfor implantation within the patient's body remote from the housingcontaining the needle, such as close to the symphyseal bone. There is alot of space available above the patient's symphyseal bone, and thedrugs could be delivered to the tip end of the needle through anappropriate conduit. If desired, one can inject pure saline solutionafter the drug injection has been completed so as to clean the conduitand needle from any drug residue. Such cleaning injection could be donethrough a different penetration area of the housing's outer wall intotissue of the patient which would not affect penis stimulation.

Preferably, the second compartments containing the drug areliquid-tightly sealed against the first compartment, with a mechanismbeing provided for individually opening a connection between the secondcompartments and the first compartment.

According to a preferred embodiment, the second compartments are mountedin a plate so as to open towards a first side of the plate and theopening mechanism is adapted to act on the second compartments from asecond side of the plate opposite the first side of the plate so thatthe compartments open to the first side of the plate. Thus, the secondcompartments may be pushed from their rear side (second side of theplate) so as to open frontward into e.g. a mixing chamber in which thecontent of the opened second compartments mixes with the content of thefirst compartment of the reservoir, such as with saline solution. Morespecifically, the second compartments may be mounted in the plate asdisplaceable drug containers and the opening mechanism may be adapted todisplace the drug containers such that they deliver their drug contentsin the manner described.

Alternatively, the plate may be rotatable so as to allow the drugcontainers to be brought into alignment with a conduit upon rotation ofthe plate. Thus, when the drug is brought into alignment with suchconduit, it may be mixed with e.g. saline solution pumped through theconduit towards the infusion needle.

According to another preferred embodiment, the second compartments aremounted on a tape wound up on a reel. A plurality of rows of the secondcompartments may be arranged on the tape in side-by-side relationship ina direction different to the winding direction of the tape. This way,the length of the tape can be reduced. It is particularly preferable ifthe tape is contained in a replaceable cassette. Thus, when all of thesecond compartments of the tape are emptied, the tape can be easilyreplaced by replacing the cassette.

As mentioned above, while the reservoir may generally be part of thehousing accommodating the at least one infusion needle, it is preferredto arrange the reservoir separate from the housing for remoteimplantation within the patient's body.

At least a section of a periphery of the first compartment of thereservoir may be made from a flexible material permitting volume changesof the first compartment by deformation of the flexible material asinfusion liquid is filled into or drawn out of the reservoir. Thus, thereservoir may be of balloon type. The flexible material may comprise apolymer membrane. A bellows construction is preferable having pre-bentcreases to reduce long term degradation.

According to a particular embodiment, drawing liquid from the reservoirmay cause a pressure decrease in at least part of the reservoir so thata negative pressure is attained as compared to the pressure in front ofthe infusion needle. For instance, the first compartment of thereservoir may comprise a gas chamber and a liquid chamber, said chambersbeing separated by a membrane, e.g. the polymer membrane. When liquid isdrawn from the liquid chamber, the pressure in the gas chamber willdecrease accordingly.

The reservoir may have an injection port for injecting liquid fromoutside the human body into the implanted reservoir. That way, thereservoir implanted in the patient's body along with the infusion devicemay be kept relatively small since the reservoir can be refilled easilyat appropriate time intervals, possibly with a doctor's aid.

Preferably, the injection port comprises a self-sealing material inrespect of penetrations caused by a replenishing syringe that would betypically used to refill the reservoir through the patient's skin. It ispreferable to implant the self-sealing injection port of the reservoirsubcutaneously in the patient's body so that it is easily accessible forrefill by means of the syringe.

While it has already been pointed out that drugs, in particular thedrugs for stimulating penis erection, may degrade upon long termstorage, another important influence on drug degradation is the storagetemperature. Some drugs have to be stored in a refrigerator at low or atleast moderate temperature. A preferred embodiment of the inventiontherefore provides for a cooling device for keeping the content withinat least one compartment of the reservoir at a temperature below 37° C.This can be achieved with relatively little energy supply if the amountof drugs to be cooled is extremely little, as explained above, and iffurthermore the drug compartment within the reservoir is thermallyinsulated. For instance, the reservoir may be comprised in an insulationchamber.

It is preferred to provide the cooling device with a heat exchanger forexchanging with the patient's body heat generated by the cooling device.Such heat exchanger may be implanted within the patient's body remotefrom the cooling device to safely dissipate the heat energy in an areawhere it cannot adversely affect the content of the reservoir.

The cooling device can be of a variety of different types. According toa first embodiment, the cooling device may contain at least twodifferent chemicals reacting with each other, thereby consuming thermalenergy which energy is drawn from the contents within the reservoir sothat a cooling effect on the contents is achieved. The two chemicals maybe provided in separate chambers and a flow control device may beprovided to bring together certain amounts of the two differentchemicals so as to control the amount of thermal energy drawn from thecontents within the reservoir.

According to a second embodiment, the cooling device may comprise atleast one Peltier element. A Peltier element is an electrothermalconverter causing a temperature difference to occur when an electriccurrent is flowing through the element, based on the Peltier effect.While one part of the Peltier element cools down, a different partthereof heats up. Such heat may again be removed by means of a heatexchanger or simply by providing the particular part generating the heatwith an enlarged surface so that the heat is directly dissipated intothe adjacent body part of the patient.

According to a third embodiment, the cooling device may be of arefrigerator-type construction. That is, heat exchanging pipes within achamber to be cooled and heat exchanging pipes outside the chamber fordissipating the heat energy absorbed in the cooling chamber are providedalong with a compressor for compressing the refrigerant gas when itexits the cooling chamber and an expansion valve for expanding therefrigerant gas before it re-enters the cooling chamber.

Turning now to the pump for advancing the infusion liquid from thereservoir to the infusion needle or needles, such pump may be a manuallydriven pump or an automatically driven pump. The manually driven pumpmay be formed from a balloon which may be manually compressed ifsuitably arranged under the patient's skin. The balloon type pump may atthe same time serve as a reservoir for the infusion liquid, inparticular for the saline solution. Preferably, however, anautomatically driven pump is used. While the type of pump is notcritical, one specific type of pump is particularly preferred. Moreparticularly, an implantable pump preferably comprises a valve devicehaving a first and a second valve member, each having a smooth surfacefacing each other so as to form a sealing contact between the first andsecond valve members and further having different liquid channels thatcan be brought into alignment by displacement of the two smooth surfacesrelative to one another while maintaining the sealing contact. This typeof pump is described in great detail in WO 2004/012806 A1. The first andsecond valve members are preferably made from a ceramic material for itsexcellent sealing capabilities over a long period of time and itsinertness to many substances.

The pump may be a membrane type pump, as also described in WO2004/012806 A1, but is not restricted to this type of pump. The membranetype pump may comprise a membrane displaceable by a piston as the pistonmoves, the piston being coupled to the valve device so as to slidablydisplace the first and second valve members relative to one another asthe piston moves. Preferably, the pump will be implanted separate fromthe housing accommodating the needle or needles for remote implantationwithin the patient's body.

Due to the space constraints within the patient's body in the area whereinjection is to take place, it is advantageous to implant as manycomponents of the system as possible remote from the first housingaccommodating the tip end of the infusion needle or needles. In thiscontext, the drive unit may comprise a mechanical drive for transmittingkinetic energy from a remote location within the patient's body to theat least one infusion needle. The mechanical drive element may comprisea rotating shaft by which a considerable distance can be bridged withinthe patient's body. The rotating shaft may, upon rotation about its axisof rotation, cause movement of the infusion needle either directly orindirectly. More specifically, the rotating shaft may be in the form ofa worm screw which, when turned, causes the infusion needle or needlesto advance and retract and/or causes the infusion needle or needles tomove laterally upon each advancement/retraction. Individual rotatingshafts or worm screws may be provided for each individual infusionneedle and/or for advancing and retracting the tip end of the infusionneedle or needles on the one hand and laterally displacing the tip endof the infusion needle or needles on the other hand. Most preferably,the rotating shaft or worm screw is flexibly bendable, so that it can befreely arranged within the patient's body.

Alternatively or in addition, the drive unit may comprise at least onewire directly or indirectly cooperating with the infusion needle so asto cause movement of the infusion needle upon actuation of the wire.Thus, the wire may be pulled at one end thereof which is located withinthe patient's body remote from the injection sites. Preferably, the wireextends through the same conduit which connects the infusion needle orneedles with the reservoir. More specifically, pulling the wire maycause the tip end of the infusion needle or needles to displacelaterally from a first to a second of the different penetration areas orfrom a first penetration site to a second penetration site within asingle one of the different penetration areas. A single pulling wire maybe sufficient to cause movement of the infusion needle in one direction,whereas a spring element or any other pretensioning means may beprovided to urge the infusion needle back to the initial startingposition or to a different starting position. Alternatively, two pullingwires may be provided to move the infusion needle back and forth in asingle dimension.

According to a preferred embodiment, the tip end of the at least oneinfusion needle is arranged for two-dimensional lateral displacement.This can be achieved by means of two pulling wires, preferablycooperating again with spring elements or other pretensioning means toprovide a counterforce to be overcome by pulling the wires.Alternatively, three pulling wires may be provided to laterally displacethe tip end of the infusion needle back and forth along at least twodirections within a two-dimensional plane.

A pulling wire may also be arranged to advance or retract the infusionneedle by pulling the wire. Again, a spring element or otherpretensioning means may be provided to urge the infusion needle back toits initial starting position or to a different starting position.

Alternatively, the drive unit may comprise a hydraulic drive fortransmitting hydraulic energy to the at least one infusion needle foradvancing the tip end thereof and/or for laterally displacing the tipend thereof. The infusion liquid itself may be used as the hydraulicmedium providing the hydraulic energy, or a secondary liquid differentfrom the infusion liquid may be used.

Further alternatively, the drive unit may comprise one or more electricmotors preferably inside the second housing accommodating the respectiveother end of the at least one infusion needle. In this case, energy maybe transmitted from a remote location within the patient's body to theat least one motor by means of appropriate wiring. Again, as in the twoafore-described alternatives, a single motor may be provided foradvancing and retracting the tip end of the infusion needle or needlesand for laterally displacing the tip end of the infusion needle orneedles, or individual motors may be provided for each individualinfusion needle and/or for advancing the tip ends of the infusion needleor needles on the one hand and laterally displacing the infusion needleor needles on the other hand.

Even further alternatively, the drive unit may comprise anelectromagnetic drive for laterally displacing and/or for advancing andretracting the tip end of the infusion needle or needles. For instance,the electromagnetic drive may comprise a group of electromagnetscomposed of a plurality of laterally spaced apart electromagnet firstparts and at least one electromagnet second part, the electromagnetsecond part cooperating with an energized one of the electromagnet firstparts. The electromagnet second part is fixedly connected to theinfusion needle or needles either directly or indirectly so that uponenergization of one or more of the electromagnet first parts theelectromagnet second part and, thus, the infusion needle or needles willbe caused to move. The arrangement of the electromagnet first parts andsecond part may be such that the electromagnet first parts are arrangedin a first plane and the electromagnet second part is movable in frontof or behind the first plane. Alternatively, the electromagnet firstparts may face each other, thereby defining a first plane between them,and the electromagnet second part may be movable within the first plane.Depending on which one or ones of the electromagnet first parts areenergized, the electromagnet second part with the infusion needle orneedles fixed thereto will move accordingly. The electromagnet firstparts preferably each include a magnetic coil.

In either one of the aforementioned alternatives, it is advantageous totransmit the driving energy through the conduit that connects the firstand second housings. That is, in the case of a mechanical drive elementin the form of a wire or rotating shaft, the wire/shaft and the infusionliquid may be guided through a common conduit. The common conduit maycomprise two separate paths, one for the shaft or wire and one for theat least one infusion needle. Such a common conduit facilitates thehandling and arrangement of the system during implantation. Similarly,the wiring for transmitting electric energy to the motor or to theelectromagnetic drive may be guided through a conduit connecting theinfusion needle or needles with the reservoir.

Where the pump and/or drive unit is not actuated manually, a drive inthe form of a motor may be arranged e.g. for electrically, magneticallyor electromagnetically actuating the pump and/or drive unit or forhydraulically actuating the pump and/or drive unit. The motor ispreferably arranged for actuating either the pump or the drive unit,thereby causing simultaneous actuation of the other, e.g. the drive unitor the pump. A motor may also be provided for actuation of any otherenergy consuming part of the infusion device. More specifically, aplurality of motors may be provided, e.g. an individual motor for eachinfusion needle and/or an individual motor for displacing the tip end ofthe infusion needle in a lateral direction on the one hand and foradvancing the tip end of the infusion needle through the housing's outerwall on the other hand.

Again, for reasons of space constraints in the area of implantation ofthe first housing or housings accommodating the tip end or ends of theat least one infusion needle, it is advantageous to remotely implant themotor within the patient's body separate from the first housing,preferably close to or within the second housing. Again, actuating meansmay be provided for manual activation of the motor or motors, suchactuating means preferably being adapted for subcutaneous implantation.

The term “motor” according to the present invention includes anythingthat employs energy other than manual power and either automaticallytransforms such energy into kinetic or hydraulic or another type ofenergy or directly uses such energy to activate the pump, drive unitand/or other part of the overall system. As such, it is possible thatpart of the drive unit also forms part of the motor, e.g. in the case ofan electromagnetically actuated drive unit.

Coupling elements may be provided either for conductive or for wirelessenergy transfer from outside the patient's body to the motor. Forinstance, the motor may be arranged for being wirelessly driven by anexternal electromagnetic field.

An energy source for providing energy to at least one of the pump, thedrive unit and the drive (motor) for driving the drive unit, and anyother energy consuming part of the system may be provided. For instance,an external energy source for use outside the patient's body, such as aprimary energy source or a battery, in particular a rechargeablebattery, that may be mounted on the patient's skin, may be used toprovide energy to the pump and/or drive unit and/or any other energyconsuming part of the system. The energy source may in particular beconnected to the at least one motor for actuating these components. Anexternal energy source for wireless energy transfer may be adapted tocreate an external field, such as an electromagnetic field, magneticfield or electrical field, or create a wave signal, such as anelectromagnetic wave or sound wave signal.

Where the energy is wirelessly transferred to the implanted components,a transforming device for transforming the wirelessly transferred energyinto electric energy may be provided. Such transforming device ispreferably adapted to be placed directly under the patient's skin so asto minimize the distance and the amount of tissue between thetransforming device and the energy supply means outside the patient'sbody.

Instead of or in addition to an external energy source, the system maycomprise an implantable energy source. While such implantable energysource may be part of or may be contained within the housingaccommodating the infusion needle or needles, it is preferred to providethe implantable energy source separate from the housing for remoteimplantation within the patient's body. Such implantable energy sourcepreferably comprises energy storage means, such as a long-life batteryor, more preferably, an accumulator. The accumulator has the advantageof being rechargeable. Preferably, the accumulator comprises arechargeable battery and/or a capacitor.

Again, coupling elements for conductive or wireless energy transfer froma primary energy source outside the patient's body to the accumulatormay be provided for charging the accumulator from outside the patient'sbody when the device is implanted in the patient's body. Similarly, theaccumulator may comprise coupling elements for conductive and/orwireless energy supply to the at least one motor of the infusion device.

A feedback subsystem, which may be part of a control unit describedbelow, can advantageously be provided to wirelessly send feedbackinformation relating to the energy to be stored in the energy storagemeans from inside the human body to the outside thereof. The feedbackinformation is then used for adjusting the amount of wireless energytransmitted by the energy transmitter. Such feedback information mayrelate to an energy balance which is defined as the balance between anamount of wireless energy received inside the human body and an amountof energy consumed by the at least one energy consuming part.

Alternatively, the feedback information may relate to an energy balancewhich is defined as the balance between a rate of wireless energyreceived inside the human body and a rate of energy consumed by the atleast one energy consuming part.

Preferably, a control unit is provided for controlling an amount ofinfusion liquid to be administered through the at least one injectionneedle. A single command from the patient to the control unit, such as asingle actuation of a press button or other type of switch, issufficient for causing the control unit to control the injection of thedrugs at two different locations within the patient's body. The controlunit may be provided for controlling at least one of the pump, the driveunit and the motor and any other energy consuming part of the systemand, where the system includes an internal or external energy source,said energy source. Again, the control unit is preferably separate fromthe housing accommodating the infusion needle or needles so as to beimplantable within the patient's body. The control unit may be adjustedsuch that the appropriate amount of drugs will be administered at theappropriate time to the particular one of the injection sites. Automaticadministration will substantially relieve the patient.

Preferably, the control unit has a data transfer port for data transferbetween an external data processing device outside the patient's bodyand the control unit implanted in the patient's body, regardless ofwhether the control unit is contained in the housing accommodating theinfusion needle or needles or whether it is implanted within thepatient's body remote from said housing. The data transfer port allowsfor monitoring the control unit to adapt the system to changing needs ofthe patient. Preferably, the data transfer port is a wireless transferport for the data transfer, so as to provide easy data exchange betweenthe control unit and the external data processing device, e.g. during avisit to the doctor. Most preferably, the control unit is programmableto further increase its adaption flexibility. Instead of or in additionto the external data processing device, the control unit may comprise anexternal component for manual operation by the patient for setting intooperation the control unit.

Apart from or as a part of the control unit, feedback may be provided onparameters relevant for the treatment. Such parameters may be eitherphysical parameters of the patient and/or process parameters of thesystem. For this purpose, at least one feedback sensor is provided fordetecting such parameters. For instance, the feedback sensor may beadapted to detect one or more parameters relating to any of thefollowing: drug level, flow volume in blood vessel, pressure, electricalparameters, distension, distance, etc.

The feedback sensors may be connected to the control unit and thecontrol unit may comprise a control program for controlling drugdelivery in response to one or more signals from the feedback sensors.In addition or alternatively, feedback data may be transferred from thecontrol unit to the external data processing device. Such feedback datamay be useful for the doctor's diagnosis.

The penetration areas of the wall or walls of the first housing orhousings within which the tip end of the infusion needle or needles aredisposed may be arranged in the patient's body at various locations. Forinstance, they may be arranged adjacent the left and right corporacavernosa and/or the two deep arteries running through the left andright corpora cavernosa and/or muscle tissue regulating blood flowthrough the patient's left and right corpora cavernosa and/or anotherkind of tissue in close proximity to the left and right corporacavernosa.

A holder may be used to secure the corpora cavernosa to the firsthousing or housings so that the housing rests in place.

Other components of the system are preferably remotely implanted, suchas adjacent the patient's symphyseal bone. As discussed above, somecomponents of the system may be implanted subcutaneously. Subcutaneousimplantation increases the possibilities of wireless energy and/or datatransfer between the implanted and the extracorporal parts of thesystem. Also, refilling the reservoir through an injection port by meansof a replenishing needle penetrating through the patient's skin issubstantially facilitated when an injection port of the reservoir isimplanted subcutaneously. In particular, the compartment of thereservoir containing the saline solution might need to be refilledfrequently, whereas the other compartments comprising individual smalldoses of the drug would need no refill. It should be understood,however, that depending upon the circumstances any implantable componentof the system may be placed in the abdomen or even in the thorax.Activating means for direct manual operation by the patient may also beprovided to be implanted subcutaneously, e.g. for setting into operationone or more of the aforementioned motors or for simply setting intooperation the control unit of the system. Such activating means may bein the form of a subcutaneously implantable switch manually operable bythe patient from outside the patient's body.

The various aforementioned features of the invention may be combined inany way if such combination is not clearly contradictory. The inventionwill now be described in more detail in respect of preferred embodimentsand with reference to the accompanying drawings. Again, individualfeatures of the various embodiments may be combined or exchanged unlesssuch combination or exchange is clearly contradictory to the overallfunction of the device. In particular, while the following descriptionof preferred embodiments specifically relates to the stimulation ofpenis erection and, more specifically, to systems for the drug deliveryat two or more different injection sites, it is to be understood thatother uses, in particular with a single needle adapted for drug deliveryat a single injection site, are also encompassed by this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the muscles of the perineum,

FIG. 2 shows a cross-section through the penis,

FIG. 3 shows a first embodiment including a single long and flexibleinfusion needle,

FIG. 4 shows a second embodiment including a single infusion needle anda motor accommodated in a common housing,

FIG. 5 shows a third embodiment including the tip ends of two long andflexible infusion needles in a common housing,

FIG. 6 shows a plan view of a part of the infusion device of FIGS. 4 and5,

FIG. 7 shows a cross-sectional view through a penetration membrane madefrom a composite material,

FIG. 8 shows a cross-sectional view through the outer wall with flaps inthe penetration area,

FIG. 9 shows a cross-sectional view through the outer wall with anactively openable door in the penetration area,

FIG. 10 shows a cross-sectional view through the outer wall with anactively openable door according to another embodiment,

FIG. 11 shows a fourth embodiment including the tip ends of a pluralityof infusion needles within a common housing,

FIG. 12 shows a fifth embodiment comprising a single infusion needle,the tip end of which is laterally and vertically displaceable,

FIG. 13 shows a sixth embodiment similar to the fifth embodiment, butwith more steps for laterally displacing the tip end of the infusionneedle,

FIG. 14 shows a seventh, spherical embodiment for obtaining athree-dimensional array of penetration sites,

FIG. 15 shows an eighth embodiment comprising the tip ends of twoinfusion needles in a common housing which are laterally and verticallydisplaceable,

FIG. 16 shows a ninth embodiment with a principle of advancing andretracting an infusion needle by means of a pull wire,

FIG. 17 shows a tenth embodiment with a principle of laterallydisplacing an infusion needle by means of pull wires,

FIG. 18 shows an eleventh embodiment with a principle of advancing andretracting an infusion needle and laterally displacing an infusionneedle by means of rotating shafts,

FIG. 19 shows the overall system of the invention implanted in apatient's body according to a first variation,

FIG. 20 shows the overall system of the invention implanted in thepatient's body according to a second variation,

FIG. 21 shows the overall system of the invention implanted in thepatient's body according to a third variation,

FIG. 22 shows drug compartments as part of the reservoir of the systemaccording to a first principle,

FIG. 23 shows drug compartments mounted on a tape wound on a reel in areplaceable cassette as part of the reservoir of the system according toa second principle,

FIG. 24 shows a part of the tape of FIG. 19 in greater detail,

FIG. 25 shows the principle of operation of the replaceable cassette ofFIG. 23,

FIG. 26 shows drug compartments as part of the reservoir of the systemaccording to a third principle,

FIG. 27 shows a cross-sectional view through the drug compartments ofFIG. 26 including an insulation chamber and cooling device,

FIG. 28 shows the principle of the cooling device of FIG. 27 incombination with a heat exchanger,

FIG. 29 shows a specific embodiment for the cooling device of FIG. 27,

FIG. 30 shows a part of the system implanted in the patient's bodycomprising separate infusion needles for the right and the left corpuscavernosum,

FIG. 31 diagrammatically shows the system of FIG. 30,

FIG. 32 shows a part of the system of FIG. 31, including a tube intowhich the tip end of the infusion needle can be advanced,

FIGS. 33A to 33C show a first and second embodiment forelectromagnetically displacing the tip end of the infusion needle in aplurality of lateral directions, and

FIGS. 34A and 34B show a third embodiment for electromagneticallydisplacing the tip end of the infusion needle in a plurality of lateraldirections.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the muscles of the perineum of a male. Reference numerals1, 2 and 3 designate the ischiocavernosus muscles, bulbospongiosusmuscles and superficial transverse perineal muscles, respectively. Thebulbospongiosus muscle surrounds lateral aspects of the bulb of thepenis at the most proximal part of the body of the penis inserting intothe perineal membrane, and further surrounds the dorsal aspect of thecorpus spongiosum 4 surrounding the urethra 5 and the left and rightcorpora cavernosa 6, 7. The ischiocavernosus 1 embraces the crus of thepenis, inserting onto the inferior and medial aspects of the crus and tothe perineal membrane medial to the crus. While the bulbospongiosusmuscle assists the erection by compressing outflow via the deep perinealvein and by pushing blood from the bulb into the body of the penis, theischiocavernosus muscle 1 maintains erection of the penis by compressingoutflow veins and pushing blood from the root of the penis into the bodyof the penis. FIG. 2 is a cross-sectional view through the penis. As canbe seen, the penis is composed of three cylindrical bodies of erectilecavernous tissue: the paired corpora cavernosa 6, 7 dorsally and thesingle corpus spongiosum ventrally. Deep arteries 9, 10 run distallynear the center of the corpora cavernosa, supplying the erectile tissuein these structures. The deep arteries of the penis are the main vesselsof the cavernous spaces in the erectile tissue of the corpora cavernosaand are therefore involved in the erection of the penis. They give offnumerous branches that open directly into the cavernous spaces. When thepenis is flaccid, these arteries are coiled, restricting blood flow.

For reasons of simplification, the following figures only display thecorpora cavernosa 6, 7. FIG. 3 shows a part of the system according to afirst embodiment. More specifically, a single long and flexibly bendableinfusion needle 11 is arranged with its tip end 13 in a first housing12, wherein the tip end 13 of the needle 11 is positioned such that itcan be advanced and retracted through a self-sealing window area 14 inthe housing's 12 outer wall 15 in a longitudinal direction 16, so as topierce the corpus cavernosum 6 or 7 located adjacent the window area 14.

Two window areas 14 are provided in the outer wall 15 of the firsthousing 12, one adjacent each of the two corpora cavernosa 6, 7. Theinfusion needle is displaceable in a lateral direction 17 between thetwo window areas 14 by means of a drive unit D. The same drive unit D ora different drive unit may cause the infusion needle 11 to be advancedand retracted. It is preferred that the drive unit for advancing and/orretracting the infusion needle, or at least the drive thereof, isdisposed in a second housing which accommodates the respective other endof the infusion needle 11 and which is remotely implanted in thepatient's body. For the purpose of enabling the tip end of the infusionneedle to be advanced and retracted, the infusion needle 11 is mountedon a slide 18 for longitudinal movement. A conduit 19 is connected tothe first housing 12 guiding the infusion needle 11 therein and, thus,protecting the infusion needle 11 against overgrowth with fibrosis. Theconduit 19 continues to guide the infusion needle within the firsthousing up to the slide 18 and is fixed to the slide so as to performthe function of a Bowden cable system, i.e. preventing the front part ofthe infusion needle 11 from flexing away when the tip end 13 of theneedle is advanced through the window area 14.

In operation, the infusion needle 11 will first be advanced with the tipend 13 thereof to penetrate one of the two self-sealing penetrationwindows 14, injection fluid containing a drug for stimulation of peniserection will be injected into the corpus cavernosum 7 through theinfusion needle 11 and, thereafter, the infusion needle 11 will beretracted again. Upon retraction of the infusion needle, the infusionneedle will be laterally displaced along the direction 17 so that thetip end 13 thereof comes to lie in front of the other of the twoself-sealing window areas 14, the infusion needle 11 will be advancedagain so that infusion liquid can be injected through the tip end 13thereof into the other corpus cavernosum 7 and then the infusion needle11 will be retracted again. At the end of this procedure, the infusionneedle 11 will return to its initial position shown in FIG. 3.

The structure of the system shown in FIG. 3 may be purely mechanical.For instance, as will be described in more detail below, the pressurewith which the infusion liquid is advanced through the needle 11 may incooperation with spring elements cause the needle 11 to be advanced,retracted and laterally displaced to the other window area 14. Thus,after two pulses of injection fluid advanced through the conduit 19towards the needle 11, the needle 11 will automatically return to itsstarting position shown in FIG. 3.

However, it is likewise possible to incorporate a motor M or a pluralityof motors M within the first housing 12 in order to achieve the desiredneedle displacement by means of the drive unit D. This is schematicallyshown in FIG. 4. Of course, the motor M will have to be provided withenergy and will need to be controlled in an appropriate manner so as toobtain the desired effect. This is not specifically shown in FIG. 4. Theenergy is preferably transmitted to the motor M from an energy sourceeither remotely implanted inside the patient's body or providedexternally of the patient's body. The number and size of the motors M inthe first housing 12 should be kept at a minimum for reason of spaceconstraints. Instead, the motors are preferably arranged remote from thefirst housing 12 in proximity to or within the afore-mentioned secondhousing.

The drive D may be configured such that after each penetration cycle(consisting of two injections) the infusion needle 11 stops at aposition different from the starting position so that the tip end 13thereof penetrates the window areas 14 in the next following injectioncycle at different sites as compared to the foregoing injection cycle.

FIG. 5 shows a third embodiment which differs from the first and secondembodiments in that it comprises two infusion needles 11 guided within acommon sheath or conduit 19 up to the first housing's outer wall 15 andguided within the first housing in separate sheaths. Thus, when bothinfusion needles 11 are advanced and retracted simultaneously along thedirection 16, injection of infusion liquid occurs at exactly the sametime. The drive unit D or a different drive unit may be used to turn theturntable 20 on which the tip ends of the infusion needles 11 aremounted, stepwise in the direction 17 so that the window areas 14 willbe penetrated by the tip ends of the infusion needles 11 at differentpenetration sites during the next following injection cycle. Again, oneor more motors M, not shown in FIG. 5, may be used for driving one ormore of the components of the drive unit D.

The principle of a guide structure for laterally displacing the tip endof the infusion needle will now be described in context with FIG. 6.Such guide structure may be used e.g. for each of the two infusionneedles 11 shown in FIG. 5 or may also be used slightly modified for thelateral displacement of the infusion needle 11 shown in FIGS. 3 and 4.

The guide structure 28 is securely fixed adjacent the self-sealingwindow area 14 which itself is implanted adjacent the patient's corpuscavernosum 7. The guide structure 28 comprises a guide pin 27 securelyconnected to the tip end of the infusion needle 11 (not shown) such thatthe infusion needle 11 cooperates with the guide structure 28. Uponadvancement or retraction of the infusion needle 11, the guide pin 27will be guided in the guide structure 28 and thereby laterally displacethe tip end of the infusion needle 11, which lateral displacement causesrotation of the turntable 20 (not shown in FIG. 6). Resilient flaps 28a, 28 b within the guide structure 28 serve to guide the guide pin 27through the entire guide structure 28 upon repeated advancement andretraction of the infusion needle 11. The guide structure 28 is designedto provide different penetration sites through the self-sealing windowarea 14 into the corpus cavernosum 7. Where it is desired, thetrajectory of guide structure 28 may include a return path 28 c for theguide pin 27 to return to its starting position shown in FIG. 6. Suchreturn action will be caused by a return spring 29 which is permanentlyfixed to a rigid part of the first housing.

The same structure can likewise be used in the embodiments shown inFIGS. 3 and 4 to displace the tip end of the single infusion needle 11laterally between the two window areas 14. Of course, the structurewould have to be slightly adapted to accommodate for the larger distanceto be overcome between the two window areas 14.

FIG. 7 shows a preferred embodiment of a penetration membrane to be usedas the self-sealing window area 14 in the outer wall 15 of the housing12. The penetration membrane 30 is made from a composite material. Thesame material can also be used for other flexible wall portions or foran infusion port that will be described below in connection with anotherembodiment. The composite material of penetration membrane 30 shown inFIG. 7 comprises an outer shape-giving layer 30 a defining a volume inwhich a self-sealing soft material 30 b is contained. Self-sealing softmaterial 30 b can be of gel type having a viscosity such that it doesnot flow through any penetrations caused by the infusion needle 11during penetration of the outer shape-giving layer 30 a. Instead of asingle outer shape-giving layer 30 a, the shape-giving layer 30 a maycomprise a plurality of layers. The outer shape-giving layer 30 apreferably comprises silicone and/or polyurethane, since such materialscan be produced to have self-sealing properties in respect ofpenetrations resulting from the infusion needle 11.

Instead of a self-sealing membrane, the window area 14 in the outer wall15 of the housing 12 may be formed by one or more flaps, as shown inFIG. 8. Two flaps 30′ being made from a resilient, biocompatiblematerial are arranged so as to form a slit which is normally closed andthrough which the infusion needle 11 can pass when it is advanced. Uponadvancement of the infusion needle 11, the needle's tip end will pushaside the normally closed flaps 30′, and when the needle 11 is retractedagain, the flaps 30′ will return to their normally closed position so asto form a seal against ingression of body liquid.

FIG. 9 shows a different embodiment. In this case, the self-sealingwindow 14 in the outer wall 15 comprises a door 30″ which can be openedby mechanical action. In the embodiment shown, the door is formed by aflap made from a resilient, biocompatible material which keeps thewindow area 14 closed in its normal position. A pull wire 300 isattached to one end of the door 30″ in order to allow for opening thedoor by pulling the pull wire 300. The pull wire 300 or any other driveconnected to the door 30″ forms part of the drive unit coupled to thefront part of the infusion needle 11. For instance, as is shown in FIG.10, the pull wire 300 may be attached directly to the infusion needle 11so that advancement of the infusion needle 11 will simultaneously causethe door 30″ to be lifted up so that the infusion needle 11 can passunderneath the door 30″ and, thus, penetrate the outer wall 15 easily.Due to the resiliency of the door material, the door 30″ willautomatically close when the force, such as the pulling force exertedvia the pull wire 300, is released. Instead or in addition, the closingaction may be supported by at least one spring element urging the doorinto its closed position.

FIG. 11 shows a fourth embodiment comprising a plurality of infusionneedles for each of the two window areas 14. In this embodiment it isnot necessary to provide a turntable by which the needles can be pivotedstepwise in order to laterally displace the needles from one penetrationsite to a different penetration site within the same window area 14.Instead, upon successive injection cycles a different one of theplurality of injection needles will be advanced and retracted for eachof the two window areas 14. Thus, the effect achieved is the same as inthe embodiment shown in FIG. 5.

FIG. 12 shows a fifth embodiment which differs from the first and secondembodiments shown in FIGS. 3 and 4 in that the tip end of the singleinfusion needle 11 is not only laterally displaceable in the direction17 between the two window areas 14 but also laterally displaceablebetween different penetration sites 21 within the same penetration area14. More specifically, the direction of lateral displacement of the tipend of the infusion needle 11 within each of said different penetrationareas 14 is perpendicular to the direction of lateral displacementbetween the different penetration areas 14. To achieve this result, thedrive unit D is configured to longitudinally advance and retract theinfusion needle 11 along a direction 16, to pivot the tip end of theinfusion needle 11 by means of a turntable 20 between the twopenetration areas 14 along a pivoting direction 17 and to raise or lowerthe tip end of the infusion needle 11 along a third direction 22perpendicular to the longitudinal direction 16. A suitable purelymechanical construction may perform this function. However, one or moremotors may also be provided to perform one and/or the other of thesefunctions. The motor or motors and, in particular, the drive unit foradvancing and retracting the infusion needle are preferably providedremote from the first housing, as already mentioned previously.

FIG. 13 shows a sixth embodiment similar to the fifth embodiment shownin FIG. 12. In contrast to FIG. 12, the tip end of the infusion needle11 is not only laterally displaceable between different penetrationsites 21 within the same penetration area 14 in a directionperpendicular to the direction of lateral displacement between the twopenetration areas 14, but is also laterally displaceable within the samepenetration area 14 in a direction parallel to the direction of lateraldisplacement between the different penetration areas 14. In other words,the tip end of the infusion needle 11 is laterally displaceable in twodimensions within the same penetration area 14.

FIG. 14 shows a seventh embodiment which enables the tip end of theinfusion needle 11 to be moved along a three-dimensional, sphericallycurved array of penetration sites. In this embodiment, a part of thefirst housing 12, more specifically the window area 14, is sphericallycurved and the front part of the infusion needle 11 is mounted in asphere so that upon rotation of the sphere along the directions 17 a and17 b the tip end 13 of the needle 11 can be moved to any position infront of the window area 14. Once an appropriate position has beenadjusted for the tip end 13, the needle 11 can be advanced on the slide18 so as to penetrate the window area 14. Instead of accommodating theslide inside the sphere, it may likewise be mounted on the outer surfaceof the sphere. Similarly, the infusion needle 11 itself can be mountedon the outer surface of the sphere. The mechanism for moving the spherealong the directions 17 a, 17 b can be of many different types, such asmechanical by means of rollers or magnetic.

FIG. 15 shows an eighth embodiment similar to the third embodiment shownin FIG. 5. That is, tip ends of two needles 11 are provided in a commonfirst housing so as to be longitudinally movable in order to advance andretract the tip ends through the penetration areas 14. Instead ofmounting the front part of the infusion needles 11 on a turntable 20, asin the embodiment of FIG. 5, so as to change the injection sites 22within a penetration area 14 upon each injection cycle, the eighthembodiment of FIG. 15 achieves the same result by raising and loweringthe tip ends of the two injection needles along a direction 22, similarto the fifth embodiment described above in relation to FIG. 12. Again,the result is that the direction of lateral displacement of the tip endsof the two infusion needles 11 within each of the two differentpenetration areas 14 is perpendicular to the direction of distancebetween the two different penetration areas 14. Of course, thisembodiment, like the sixth embodiment shown in FIG. 13, can also bemodified such that the tip ends of the two infusion needles 11 arelaterally displaceable in two dimensions within the same penetrationarea 14.

FIG. 16 shows a ninth embodiment with a principle of advancing andretracting the infusion needle 11 by means of a pull wire 101. The pullwire 101 is redirected about a pin 102 such that by pulling the wire 101at an end remotely located somewhere in the patient's body the tip endof the infusion needle 11 will be advanced through the window of thehousing 12. A helical spring provides a counterforce so that theinfusion needle 11 will be retracted once the pulling force on the pullwire 101 is released. This principle can be combined with otherembodiments described hereinbefore and hereinafter. Instead of thehelical spring 104, a second pull wire may be provided to retract theinfusion needle 11. It is even possible to use a single pull wire 101running around two pins 102 in a loop, so that pulling the wire 101 inthe one direction or in the other direction will cause advancement orretraction of the infusion needle 11.

The pull wire 101 and the infusion needle are guided in a common sheath103. The common sheath 103 has various functions. First, it givessupport to the pull wire 101 in bending sections. Second, it facilitatesimplantation of the infusion needle 11 along with the pull wire 101.Third, it protects the pull wire 101 against any build-up of fibrosis.

FIG. 17 shows a tenth embodiment which involves remotely actuated pullwires 105, 106 guided within a common sheath 103 along with the infusionneedle 11. The pull wires 105 and 106 are directly attached to the frontend of the infusion needle 11 on opposite sides thereof so that the tipend of the infusion needle 11 which is mounted on a turntable 20 will belaterally displaced in the one direction or in the other directiondepending on whether the wire 105 or the wire 106 is pulled. Instead ofusing two wires 105, 106, one of the wires may be replaced with apretensioning means, such as the helical spring 104 in FIG. 16. Inaddition, a further wire, in particular third wire (not shown), may beprovided for lateral displacement of the infusion needle 11 in a furtherdirection, so that a two-dimensional lateral displacement can beachieved by pulling the appropriate wires. In particular, due to thefact that the infusion needle 11 is long and flexibly bendable, one candispense with the turntable 20 and achieve accurate lateral displacementof the tip end of the infusion needle 11 by pulling the appropriate oneof three pull wires which are attached either directly or indirectly tothe circumference of the front end of the infusion needle at regularlyspaced intervals. The pull wires may alternatively be attached to anelement other than the infusion needle 11, provided that the infusionneedle 11 is connected to such other element, so that when the otherelement is moved or turned by pulling one or more of the wires the tipend of the infusion needle 11 will be displaced accordingly.

FIG. 18 shows an eleventh embodiment with a different principle ofadvancing and retracting the tip end of the infusion needle, on the onehand, and laterally displacing the tip end of the infusion needle 11, onthe other hand. Instead of pull wires, rotating shafts 107, 108 areprovided. The drive for driving the rotating shafts 107, 108 is remotelylocated somewhere in the patient's body. The front ends of the rotatingshafts have a threading 109, 110, e.g. in the form of a worm screw,meshing with the teeth of a rack 111, 112 formed either directly orindirectly on the infusion needle 11 and on the turntable 20,respectively. Thus, by turning the rotating shaft 107, the infusionneedle 11 will advance or retract, as the case may be, due to thecooperation of the worm screw 109 and the rack 111. The gearing 109, 111may likewise be arranged remote from the first housing, i.e. within thesecond housing accommodating the respective other end of the needle.Similarly, by turning the rotating shaft 108, the infusion needle 11will be displaced laterally in the one or the other direction due to thecooperation of the worm screw 110 and the rack 112 of the turntable 20.Again, the rotating shafts 107, 108 are guided in a common sheath 103along with the infusion needle 11.

In FIGS. 17 and 18, the action of the pull wires 105, 106 and therotating shaft 108 make it possible to laterally displace the tip end ofthe infusion needle 11 between two different penetration areas and/orfrom a first penetration site to a second penetration site within asingle penetration area.

FIG. 19 shows a first variation of an overall system comprising any oneof the first to eleventh embodiment described above. Specifically shownin the variation shown in FIG. 19 is a first housing 12 accommodatingthe tip end of a single infusion needle 11 and a drive unit D asdescribed in relation to FIG. 12. The housing 12 is implanted with itswindow areas 14 positioned adjacent the corpora cavernosa 6, 7, of whichwindow areas 14 only one is shown in FIG. 19. A motor M is contained inthe housing 12 for driving the drive unit D. While the motor M in thehousing 12 may be designed to move the front end of the infusion needle11 in all directions as indicated in FIG. 19, it is possible and evenpreferable to cause advancement and retraction of the front end of theinfusion needle by advancing and retracting the entire infusion needlefrom its rear end using an additional motor, so as to minimize the motorsize in the housing 12 for reasons of space constraints in the injectionarea. The additional motor may be accommodated in a separate secondhousing—not shown in FIG. 19—along with the rear end of the infusionneedle and possibly along with further components remotely implanted inthe patient's body. The motor M within the housing 12 (and likewise theafore-mentioned additional motor) is controlled by means of a controlunit C₂ constituting the implantable part of a control system whichfurther comprises an external data processing device C₁ by whichcommands and any other kind of data can be sent to the control unit C₂.For instance, the external data processing device C₁ may be used toinitiate an injection cycle from outside the patient's body, this beingdone wirelessly as indicated by arrow 23. The implanted control unit C₂not only controls the motor M inside the housing 12 but also controlsthe energy supply from an accumulator A to the motor M inside thehousing 12.

The external data processing device C₁ may likewise be used to programthe implanted control unit C₂. Also, a data transfer port fortransferring data between the external data processing device C₁ and theimplanted control unit C₂ may be adapted to transfer data in bothdirections.

A feedback sensor F implanted inside the patient's penis is shown hereas being connected to the motor M inside the housing 12 and may likewisebe connected to the implantable control unit C₂. The feedback sensor Fcan sense one or more physical parameters of the patient, such as thedrug level inside the corpora cavernosa, the flow volume through thecorpora cavernosa, the pressure inside the corpora cavernosa and thelike. Other feedback sensors may be provided at a different location soas to sense process parameters of the system, such as electricalparameters, distention, distance and the like.

The conduit 19 guides the infusion needle 11 from a reservoir comprisingcompartments R₁ and R₂ and accommodates the wiring 24 for transmittingelectric energy from the energy source A to the motor M inside thehousing 12.

In the variation of the entire system shown in FIG. 19, the reservoircomprises a first compartment R₁ with e.g. a saline solution includedtherein, and a second compartment R₂ with e.g. a drug in powder form orfreeze-dried form included therein. A pump P driven by a second motor M₂is arranged to pump infusion liquid from the reservoir R₁ to theinfusion needle 11. The infusion liquid pumped by the pump P will passthrough a mixing chamber 26 into which drugs will be released from thereservoir R₂ in appropriate time coordination. The motor M₂ or adifferent motor may cause the drugs to be released from the secondreservoir R₂. The motor M₂ is also controlled by the control unit C₂.Thus, infusion liquid pumped via the pump P from the relatively largefirst reservoir R₁ through the mixing chamber 26, in which it is mixedwith the drugs released from the second reservoir R₂, will reach theinfusion needle 11 which has meanwhile penetrated the self-sealingwindow area 14 of the housing 12 and will flow into the corpuscavernosum 7.

In addition to or instead of the control unit C₂, a pressure sensitiveswitch for activating the motor M inside the housing 12 and/or the motorM₂ may be arranged subcutaneously.

Although the embodiment shown in FIG. 19 may comprise one of a greatvariety of reservoir types, a particular reservoir type will now bedescribed. The volume of the reservoir R₁ is divided into two sectionsby means of a membrane 31. One section is filled with gas whereas theother section is filled with the infusion liquid (saline solution). Aninfusion port 32 allows for refilling the reservoir R₁ with infusionliquid by means of a replenishing needle. When the reservoir R₁ is inits full state, the gas section is at ambient pressure orover-pressurized. As infusion liquid is drawn from the reservoir R₁ bymeans of the pump P upon each infusion cycle, the pressure in the gassection will decrease below ambient pressure, i.e. to a negativerelative value. Depending upon the particular type of pump P, it may beadvantageous to provide a single acting ball valve to prevent anybackflow from the pump P to the reservoir R₁.

There are various ways of providing the motors M and M₂ with energy. Inthe variation shown in FIG. 19, energy is supplied from outside thepatient's body either for direct use by the motors and/or for chargingthe accumulator A, which may be in the form of a rechargeable batteryand/or a capacitor. An extracorporal primary energy source E transmitsenergy of a first form through the patient's skin 100 to an energytransforming device T which transforms the energy of the first form intoenergy of a second form, such as electric energy. The electric energy isused to recharge the accumulator A which provides secondary energy tothe motor M upon demand.

The external primary energy source E may be adapted to create anexternal field, such as an electromagnetic field, magnetic field orelectrical field, or create a wave signal, such as an electromagneticwave or sound wave signal. For instance, the energy transforming deviceT as shown in FIG. 19 may act as a solar cell, but adapted to theparticular type of wave signal of the primary energy source E. Theenergy transforming device T may also be adapted to transformtemperature changes into electrical energy.

Instead of the external primary energy source E, an implantable primaryenergy source E may be used, such as a regular long-life battery insteadof the accumulator A.

The energy signal may also be used to transmit signals from the externaldata processing device C₁ by appropriate modulation of the energysignal, regardless of whether the energy is transmitted wirelessly or bywire, the energy signal thereby serving as a carrier wave signal for thedigital or analog control signal. More particularly, the control signalmay be a frequency, phase and/or amplitude modulated signal.

FIG. 20 shows a second variation of the entire system which basicallydiffers from the system of FIG. 19 only in that the motor M inside thehousing 12 is dispensed with. Instead, the motor M₂ is used to drive thedrive unit D. This is achieved by means of a rotating shaft 33 in theform of an elastically bendable worm screw, the rotating shaft 30replacing the wiring 24 of the system shown in FIG. 19. Alternatively,since the infusion needle 11 is long and flexible, the infusion needlemay be advanced by engagement of two helical gears, one of which isformed on the rear end of the infusion needle, or by a similar gearingcooperating with the infusion needle's rear end.

FIG. 21 shows a third variation of the entire system which operatespurely mechanically. The reservoir R₁ containing the infusion liquid,i.e. the saline solution, is of balloon type, thereby functioning bothas a reservoir and as a pump if it is compressed manually from outsidethe patient's body. The pressure generated in the reservoir R₁ will acton the reservoir R₂ containing the drug. Upon a certain pressure, thedrug will be released from the reservoir R₂ into the mixing chamber 26and upon further increase of the pressure the infusion liquid will beallowed to enter the mixing chamber 26, mix with the drug released fromthe reservoir R₂, flow towards the infusion needle 11, and build uppressure on the infusion needle 11 such that the drive unit D is causedto advance the infusion needle 11 through the self-sealing window area14 into the patient's corpus cavernosum. Once the pressure is released,the infusion needle 11 will retract automatically due to mechanicalspring forces or the like and move into a different position in which itcan penetrate the second of the two self-sealing window areas 14 whenthe reservoir R₁ is compressed again. Where two infusion needles 11 areprovided, a single compressing action on the reservoir R₁ would besufficient to inject the drug into both the left and right corporacavernosa.

FIG. 22 shows a first principle of how drugs within a plurality ofcompartments 34 of the reservoir R₂ can be released one at a time by apurely hydromechanical solution. As the infusion liquid is urged fromthe reservoir R₁ towards the conduit 25 leading to the infusion needleor needles, it is first blocked by a spring-loaded ball valve 34 whichopens only when a certain pressure is exceeded. The pressure building upin front of the ball valve 34 is guided by means of a stepper valve Vsequentially onto one of a plurality of compartments 35. Thecompartments are each formed as a cavity 35 within a piston 36. Once acertain pressure is exceeded, the piston 36 will be pushed into aposition where the compartment 35 is in flow communication with a mixingchamber 26. In the state shown in FIG. 22, three pistons 36 have alreadybeen pushed into such position. When the pressure in the reservoir R₁ isfurther increased, the spring force of the ball valve 34 will beovercome and the infusion liquid urged from the reservoir R₁ towards theconduit 25 will take with it the drug that has been released into themixing chamber 26.

FIGS. 23 to 25 show a second principle of realizing the reservoir R₂comprising a plurality of small drug compartments 35, 35 a, 35 b. Thedrug compartments are integrally formed in a tape 201 which is wound ona first reel 202 and can be unwound from said first reel 202 onto asecond reel 203. The reels 202, 203 and the tape 201 are contained in acassette 200 which may be inserted in the entire system so as to formpart of the reservoir. The cassette 200 is preferably replaceable.

As can be seen in FIG. 24, the compartments 35, 35 a, 35 b containingthe drug e.g. in powder form or freeze-dried form are arranged in aplurality of rows as seen in the transporting direction (indicated bythe arrow). However, the compartments 35 of one row are a certaindistance offset in the transporting direction from the compartments 35 aand 35 b of the other rows. Thus, when the tape 201 is wound from reel202 to reel 203, it is guided through a conduit 204 forming part of thecassette 200 through which the infusion liquid is pumped from thereservoir R₁ to the infusion needle or needles, and the compartments 35,35 a, 35 b will enter the conduit 204 one after the other.

While it is conceivable to open one of the compartments 35, 35 a, 35 bthat has entered the conduit 204 by mechanical action, such as a hammeror piercing element, the opening of the compartments 35 in theembodiment shown in FIGS. 23 to 25 needs no further action other thanwinding the tape 201 onto the reel 203. That is, as can be seen fromFIG. 25, when the tape 201 enters the conduit 204 through a first slit205, the compartments 35 will not be damaged due to the fact that theslit 205 is relatively wide and is closed by two soft sealing lips 206.However, when the tape 201 exits the conduit 204 on the other sidethereof, it will have to pass a narrower second slit 207 with frontedges 208 that are not resilient. The compartments 35 will thereforeburst on their way out of the conduit 204 when they slip between theedges 208 of the narrow slit 207. Soft seals 209 in the slit 207 preventliquid from leaking from the conduit 204.

The entry 210 and the exit 211 of the conduit 204 within the cassette200 each include a valve that automatically closes when the cassette 200is removed from the system and automatically opens when the cassette 200is installed in the system. This allows for replacement of the cassette200 without adversely affecting the remaining components of the overallsystem.

FIGS. 26 and 27 show a third principle of realizing the reservoir R₂comprising a plurality of small drug compartments 35. While FIG. 26shows a cross-sectional plan view according to section BB in FIG. 27,FIG. 27 shows a cross-sectional side view thereof according to sectionAA in FIG. 26. The compartments 35 containing the drug in powder form orfreeze-dried form are arranged in a rotatable plate 37. A motor M₂ isprovided to rotate the plate 37 about an axis 38. The motor M₂ iscontrolled to advance the plate 37 stepwise so as to bring onecompartment 35 at a time in line with the conduit 39 connecting thereservoir R₁ containing the saline solution with the infusion needle orneedles. Energy is supplied to the motor M₂ from the accumulator A viathe control unit C₁.

The rotatable plate 37 is mounted in a fixed base plate 39 which itselfis fixedly mounted in a housing 40 insulating the base plate 39 and therotatable plate 37 thermally against an outer housing 42. A coolingdevice 41 is provided to cool a liquid surrounding the base plate 39 androtatable plate 37 down to a temperature below 37° C. This serves toprotect the drugs inside the compartment 36 from degrading too quickly.The accumulator A supplies the cooling device 41 with energy.

FIG. 28 shows a general principle of cooling the reservoir R₂ containingthe drug to be cooled. The cooling device 41 may be an electrothermalcooler, i.e. based on the Peltier effect consuming electric energy, ormay be of the refrigerator type. Accordingly, the cold part of thecooler 41 is placed on the side to be cooled whereas the warm part ofthe cooling device 41 is placed on the other side so that the heatenergy can be dissipated to the outside. An increased surface 41 a onthe warm side of the cooling device 41 serves to increase heatdissipation. Furthermore, a heat exchanging fluid may be passed througha conduit 41 b along the increased surface 41 a to transfer thedissipated heat energy to a remote location within the patient's bodywhere the heat is dissipated into the patient's body through a specificheat exchanging surface 41 c.

FIG. 29 shows a different principle of cooling the drugs contained inthe reservoir R₂. In this embodiment, two chemicals X1 and X2 arecontained separate from each other in respective compartments of thecooling device 41. When the chemicals X1 and X2 are brought together,they will react with each other and such reaction will consume energywhich is absorbed as thermal energy from the surroundings. By means oftwo pistons 41 d, 41 e, the chemicals X1, X2 are dispensed into acooling line 41 f in a controlled manner, which cooling line ispreferably in contact with the housing 40 containing the reservoir R₂.The chemical mixture X1-X2 displaced within the cooling line 41 f willflow back into the chamber containing the chemicals X1, X2, but onto theother side of the pistons 41 d, 41 e.

A further embodiment is shown in FIG. 30. In this embodiment, again, twoseparate long and flexible infusion needles 11 are provided with theirrespective front ends accommodated in a housing 12, one infusion needlefor each of the left and right corpora cavernosa. However, unlike thepreviously discussed embodiments, the two needles each have their ownhousing 12 implanted in the patient's body with their respectiveself-sealing window area 14 adjacent the left and right corporacavernosa, respectively. This principle is shown in FIG. 31 in moredetail with respect to one of the two needles. The drive unit Dcomprises a piston 50, to which the hollow infusion needle 11 isattached. The piston 50 separates a first chamber 51 a in front of thepiston 50 and a second chamber 51 b behind the piston 50. While thepressure in the first chamber 51 a corresponds to the pressure exertedby the pump P via the conduit 25, the pressure in the second chamber 51b can be kept at a lower value. The second chamber 51 b may be filledwith a liquid, such as the infusion liquid, and the liquid may be urgedinto a flexible volume 52. The flexible volume 52 could be of simpleballoon type so as to fill up without exerting any strong counterforce.

Instead of the flexible volume 52, a conduit 53 may connect the secondchamber 51 b with the reservoir R₁. Thus, when the needle 11 isadvanced, liquid will be dispelled from the second chamber 51 b throughthe conduit 53 into the reservoir R₁, and as the needle 11 is retractedby means of a return spring 55, liquid will be drawn from the reservoirR₁ through the conduit 53 back into the second chamber 51 b.

The injection process is carried out as follows. As the pressure isincreased in the first chamber 51 a by means of the pump P remote fromthe housing 12 accommodating the tip end 13 of the infusion needle 11,the entire infusion needle 11 which is guided in the conduit 19 will bedisplaced against the force of the spring 55 of the drive unit B. Thus,the tip end 13 of the infusion needle 11 will penetrate through theself-sealing window area 14 press-fitted into the wall 15 of the housing12 and will further penetrate any fibrosis having built up in front ofthe housing. When the return spring 55 is completely compressed and thepressure built up by the pump P is further increased, a ball valve 56will be displaced against a second return spring 57 which is strongerthan the first return spring 55. That way, as long as the pressure isheld at a sufficiently high level, infusion liquid will be pumped fromthe reservoir R₁ through the conduit 25, the hollow infusion needle 11and the needle's laterally arranged exit port into the patient's body.Upon pressure release, the ball valve 56 will close due to the returnsprings 55 and 57, and then the needle 11 will be retracted to itsinitial position shown in FIG. 22.

It may be advantageous not to pierce any living tissue by means of theinjection needle 11 once it is advanced through the outer wall 15 of thehousing 12. Therefore, as shown in FIG. 32, a tube 58 may be placed infront of the window area 14. The cross-sectional form of the tube 58 maybe adapted to the cross-sectional form of the window area 14, i.e. wherethe window area 14 is rectangular, the tube 58 likewise has arectangular cross-section.

The exit end of the tube 58 has an open area 59 sufficiently large toprevent growth of fibrosis from spanning over the open area. Fibrosiswill slowly grow into the tube along the tube's inner surface, before itreaches the window area 14 after a relatively long time. The tip end 13of the needle 11 will therefore not have to penetrate any fibrosisduring the first while after implantation of the system. Preferably, theopen area 59 has an opening width of at least 3 mm. The length of thetube 58 may be in the range of 4 mm to 30 mm. The opening width 59 andthe length of the tube 58 should be adjusted such that the substanceinjected into the tube 58 can safely seep into the patient's body. Thus,the longer the tube is, the larger the opening width thereof should be.

FIGS. 33A and 33B show a first embodiment for displacing the tip end ofthe infusion needle 11 in two or more different directions, i.e. atwo-dimensional displacement. More specifically, FIG. 33A shows a planview, whereas FIG. 33B shows a side elevational view schematically. Ascan be seen, a plate 60 to which the infusion needle 11 is fixedlymounted has a projection 61 extending into a frame 62 within which theprojection 61 is free to move in any direction. Electromagnetic coils 63are mounted on the sides of the frame 62 and are individuallyenergizable. The electromagnetic coils 63 constitute the first part ofan electromagnetic drive whereas the projection 61 is configured toconstitute the second part of the electromagnetic drive. Thus, when oneor more of the electromagnetic coils are energized, an electromagneticfield is created in the frame 62 and the electromagnet second part, i.e.the projection 61, will adjust its position within such fieldaccordingly. Due to the fact that the front end of the infusion needle11 is fixedly mounted to the plate 60, the infusion needle 11 will movealong with the projection 61. This way, the tip end of the infusionneedle 11 can be displaced laterally and can also be advanced andretracted.

More preferably, however, the infusion needle 11 is attached to theelectromagnetic drive in a different manner, namely perpendicular to theplane defined by the electromagnetic coils 63 (rather than in parallelas in FIG. 33B). As a result, the tip end of the infusion needle will bedisplaceable in a plurality of lateral directions rather than beingadvanceable and retractable. The drive unit for advancing and retractingthe infusion needle 11 is instead preferably connected to the rear endof the long and flexibly needle.

Alternatively, the electromagnetic drive may be such as to displace thetip end of the infusion needle in any lateral direction and, inaddition, to advance and retract the infusion needle. This can beachieved e.g. with a structure as schematically shown in FIG. 33Crelating to a second embodiment for displacing the tip end of theinfusion needle 11. FIG. 33C shows an elevational side view similar toFIG. 33B, but the electromagnetic coils 63 do not define a single plane,but rather a plurality of planes is defined one above the other byproviding additional electromagnetic coils 63 in a vertical direction.The top plan view would be similar to FIG. 33A. This way, theelectromagnet second part 61 fixedly connected to the needle 11 moveswithin a three-dimensional frame 62 depending on the energization ofrespective ones of the magnetic coils 63.

FIGS. 34A and 34B shows a plan view and a side view of a thirdembodiment of an electromagnetic drive for moving the tip end of theinfusion needle 11 in a plurality of directions. In this embodiment, theelectromagnetic coils 63 constituting the electromagnet first parts arearranged in a first plane and the electromagnet second part constitutedby the protrusion 61 fixedly connected to the infusion needle 11 via theplate 60 is movable in a plane in front of or behind the plane definedby the electromagnet first parts. However, the electromagnetic coils 63are oriented differently in this third embodiment. Again, depending uponthe energization of the individual electromagnetic coils, theelectromagnet second part, i.e. the protrusion 61, will adjust itsposition in the created electromagnetic field within the frame 62.

A method of treating a human being (or an animal) by implanting at leastpart of the system in the patient's body comprises the steps of cuttingthe skin, dissecting free a first area near the left and right corpuscavernosum, placing the at least one first housing accommodating the tipend or ends of the at least one infusion needle within said dissectedarea such that the tip end, when penetrating the housing's outer wall,can penetrate into the left and right corpus cavernosum and/or the twodeep arteries of the right and left corpus cavernosum and/or into muscletissue regulating blood flow to the patient's left and right corpuscavernosum and/or into another kind of tissue in close proximity to thepatient's left and right corpus cavernosum allowing stimulation oferection of the two corpora cavernosa, placing at least one secondhousing accommodating the respective other end or ends of the at leastone infusion needle within the patient's body remote from the at leastone first housing, and finally closing at least the skin afterimplantation of at least parts of the system.

Where parts of the system are implanted remote from the corporacavernosa, a second area remote from the first area may be dissectedfree in order to place e.g. the at least one reservoir in the patient'sbody at the remote second area, with a conduit connecting the reservoirwith the rear end of the at least one infusion needle accommodated inthe at least one second housing. In this case, it is preferable to placethe second housing and/or the reservoir adjacent the patient'ssymphyseal bone.

One or more of the following elements may be placed within the patient'sbody remote from the housing or housings accommodating the at least oneneedle:

-   -   at least one drive unit for advancing and retracting the tip end        of the infusion needle,    -   a reservoir for supplying to the infusion needle a substance to        be injected into the patient's body,    -   a pump (P) for advancing the substance from the reservoir to the        at least one infusion needle,    -   at least one motor (M, M₂) for actuation of the drive unit (D)        or a drive driving the drive unit, and/or the pump (P) or any        other energy consuming part of the system,    -   energy storage means (A) for providing the at least one motor        with energy,    -   galvanic coupling elements between either an external energy        source (E) or the energy storage means (A) and the motor (M, M₂)        for transmitting energy to the motor in contacting fashion,    -   wireless coupling elements adapted to connect either the motor        (M, M₂) or the energy storage means (A) or both to an        extracorporal primary energy source for transmitting energy to        either the motor or the energy storage means or both in        non-contacting fashion,    -   control unit (C1) for controlling the motor (M, M₂),    -   a data transmission interface for wirelessly transmitting data        from an external data processing device (C₂) to the control unit        (C₁),    -   the feedback sensor (F),    -   wireless energy transforming means, and    -   the injection port (32) for refilling the reservoir (R₁).

The invention claimed is:
 1. An at least partly implantable system forinjecting a substance into a patient's body, comprising at least oneflexibly bendable infusion needle with a tip end of each of said atleast one infusion needle arranged in at least one first housing forpenetrating the first housing's outer wall in at least one penetrationarea and having the respective other end arranged in at least one secondhousing, the first and second housings being adapted for implantationinside the patient's body, wherein the at least one second housing isprovided for implantation inside the patient's body remote from the atleast one first housing and wherein the injection needle is sufficientlylong to bridge the distance from the at least one second housing forremote implantation to the at least one first housing and furtherthrough the first housing up to the outer wall of the first housing, andat least one drive unit adapted for being coupled to the at least oneinfusion needle and arranged at least for advancing the tip end of theat least one infusion needle so that the at least one infusion needlepenetrates with the tip end or ends thereof said at least one firsthousing's outer wall in said at least one penetration area to inject thesubstance into the patient's body, wherein at least in the at least onepenetration area the outer wall is made from a material which isself-sealing in respect of penetrations resulting from said at least oneinfusion needle.
 2. The system of claim 1, wherein the self-sealingmaterial forms at least two window areas in said outer wall, said windowareas being positioned for penetration by the tip end or ends of the atleast one infusion needle.
 3. The system of either of claims 1 to 2,wherein the self-sealing material comprises a penetration membraneintegrated in the outer wall.
 4. The system of claim 3, wherein thepenetration membrane is sealingly press-fitted into the outer wall. 5.The system of claim 1, wherein the self-sealing material comprises atleast one polymer selected from the group of materials comprisingsilicon and polyurethane.
 6. The system of claim 1, wherein theself-sealing material is made from a composite material.
 7. The systemof claim 6, wherein the composite material comprises at least one outershape-giving layer and a self-sealing soft material contained within theouter layer.
 8. The system of claim 7, wherein the self-sealing softmaterial is a gel.
 9. An at least partly implantable system forinjecting a substance into a patient's body, comprising at least oneflexibly bendable infusion needle with a tip end of each of said atleast one infusion needle arranged in at least one first housing forpenetrating the first housing's outer wall in at least one penetrationarea and having the respective other end arranged in at least one secondhousing, the first and second housings being adapted for implantationinside the patient's body, wherein the at least one second housing isprovided for implantation inside the patient's body remote from the atleast one first housing and wherein the injection needle is sufficientlylong to bridge the distance from the at least one second housing forremote implantation to the at least one first housing and furtherthrough the first housing up to the outer wall of the first housing, andat least one drive unit adapted for being coupled to the at least oneinfusion needle and arranged and adapted at least for advancing the tipend of the at least one infusion needle so that the at least oneinfusion needle penetrates with the tip end or ends thereof said atleast one first housing's outer wall in said at least one penetrationarea to inject the substance into the patient's body, wherein the outerwall comprises at least one flap in the at least one penetration areathrough which the tip end or ends of the at least one infusion needlecan pass, said flap being arranged to be pushed aside by the tip end ofthe at least one infusion needle upon advancement of said infusionneedle.
 10. An at least partly implantable system for injecting asubstance into a patient's body, comprising at least one flexiblybendable infusion needle with a tip end of each of said at least oneinfusion needle arranged in at least one first housing for penetratingthe first housing's outer wall in at least one penetration area andhaving the respective other end arranged in at least one second housing,the first and second housings being adapted for implantation inside thepatient's body, wherein the at least one second housing is provided forimplantation inside the patient's body remote from the at least onefirst housing and wherein the injection needle is sufficiently long tobridge the distance from the at least one second housing for remoteimplantation to the at least one first housing and further through thefirst housing up to the outer wall of the first housing, and at leastone drive unit adapted for being coupled to the at least one infusionneedle and arranged and adapted at least for advancing the tip end ofthe at least one infusion needle so that the at least one infusionneedle penetrates with the tip end or ends thereof said at least onefirst housing's outer wall in said at least one penetration area toinject the substance into the patient's body, wherein the outer wallcomprises at least one door in the at least one penetration area,wherein a drive is connected to the at least one door for activelyopening the door so as to allow for the tip end or ends of the at leastone infusion needle to be advanced through the opened door.
 11. Thesystem of claim 10, wherein the drive connected to the door forms partof the drive unit coupled to the infusion needle.
 12. The system ofeither of claims 10 to 11, wherein the door comprises a normally closed,resilient flap.
 13. The system of claim 10, comprising at least onespring element urging the door into its closed position.
 14. An at leastpartly implantable system for injecting a substance into a patient'sbody, comprising at least one flexibly bendable infusion needle with atip end of each of said at least one infusion needle arranged in atleast one first housing for penetrating the first housing's outer wallin at least one penetration area and having the respective other endarranged in at least one second housing, the first and second housingsbeing adapted for implantation inside the patient's body, wherein the atleast one second housing is provided for implantation inside thepatient's body remote from the at least one first housing and whereinthe injection needle is sufficiently long to bridge the distance fromthe at least one second housing for remote implantation to the at leastone first housing and further through the first housing up to the outerwall of the first housing, and at least one drive unit (D) adapted forbeing coupled to the at least one infusion needle and arranged andadapted at least for advancing the tip end of the at least one infusionneedle so that the at least one infusion needle penetrates with the tipend or ends thereof said at least one first housing's outer wall in saidat least one penetration area to inject the substance into the patient'sbody, wherein the at least one infusion needle (11) is arranged forpenetrating the at least one first housing's outer wall (15) in at leasttwo different penetration areas (14).
 15. The system of claim 14,wherein the at least one drive unit (D) is arranged for displacing thetip end or ends of the at least one infusion needle so that the at leastone infusion needle penetrates, upon advancement of the tip end or endsthereof, at least two of said different penetration areas.
 16. Thesystem of either of claims 14 to 15, wherein the system is adapted suchthat the at least one infusion needle penetrates said at least twodifferent penetration areas upon a single command or single action fromthe patient.
 17. The system of claim 14, wherein the at least one driveunit is adapted for displacing the at least one infusion needle in suchway that it penetrates, upon advancement, with the tip end or endsthereof said at least two different penetration areas eithersimultaneously or in immediate time succession.
 18. The system of claim14, wherein the system is adapted such that the time delay between thepenetration of a first and a second of said at least two differentpenetration areas does not exceed 120 seconds, and preferably does notexceed 60 seconds.
 19. The system of claim 14, wherein the system isadapted such that once the at least one infusion needle has beenretracted from a first of the at least two different penetration areas,advancement of the at least one infusion needle to a second of the atleast two different penetration areas is initiated.
 20. The system ofclaim 14, wherein at least one infusion needle is provided for each ofat least two of the different penetration areas.
 21. The system of claim20, wherein two or more infusion needles are provided for each of saidtwo different penetration areas and are arranged for penetratingdifferent penetration sites within each of said two differentpenetration areas.
 22. The system of claim 21, wherein the drive unit isconfigured to advance and retract one infusion needle in each of saidtwo different penetration areas at one time, and to advance and retracta different infusion needle in each of said two different penetrationareas at a different time.
 23. The system of claim 20, wherein the tipends of at least two infusion needles are contained in a common one ofsaid at least one first housing in spaced apart relationship, the driveunit being configured to advance and retract the at least two infusionneedles so as to penetrate the outer wall of the common first housingwith their respective tip ends in said at least two differentpenetration areas.
 24. The system of claim 23, wherein the drive unit isconfigured to advance and retract the at least two infusion needlessimultaneously.
 25. The system of either of claims 23 to 24, wherein thedrive unit is configured to laterally displace the tip ends of the atleast two infusion needles to different penetration sites within each ofsaid at least two different penetration areas.
 26. The system of claim25, wherein the drive unit is configured to laterally displace the tipends of the at least two infusion needles simultaneously.
 27. The systemof claim 25, wherein a direction of lateral displacement of the tip endsof the at least two infusion needles within each of said at least twodifferent penetration areas is the same as the direction of distancebetween said two different penetration areas.
 28. The system of claim25, wherein a direction of lateral displacement of the tip ends of theat least two infusion needles within each of said at least two differentpenetration areas is different from, in particular perpendicular to, thedirection of distance between said at least two different penetrationareas.
 29. The system of claim 23, wherein the drive unit is configuredto displace the tip ends of each of the at least two infusion needles inat least two different lateral directions.
 30. The system of claim 23,wherein the drive unit is configured to displace the tip ends of each ofthe infusion needles along a three-dimensional array of penetrationsites.